Fish Fossils Reveal Internal Sexual Reproduction

Scientists at Museum Victoria in Melbourne and the Natural History Museum in London have discovered internal sexual reproduction in early fish fossils, some 30 million years earlier than previously believed.

Fossils of the 380 million-year-old fish Incisoscutum richiei, or armored placoderm fish, revealed females carrying fossilized embryos. This provides the earliest evidence for internal sexual reproduction and internal incubation of offspring that included bearing live young. Subsequent analysis of the male of the species also uncovered a previously overlooked pelvic fin not present on the female, supposedly used to grip the female during reproduction.

Researchers expected prehistoric fish to have a much more simple reproductive strategy, similar to the external fertilization of today's fish species where sperm and egg combine in the water and embryos develop outside the body. The fossilized fish and embryos are from the Gogo dig site in Western Australia and are the oldest known evidence of a vertebrate mother.

These results were published in the February 26th edition of Nature.

Source: Yahoo!